/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.xml.security.utils.resolver;

import org.apache.xml.security.signature.XMLSignatureInput;

/**
 * During reference validation, we have to retrieve resources from somewhere.
 *
 * Extensions of this class must be thread-safe.
 */
public abstract class ResourceResolverSpi {

    /**
     * This is the workhorse method used to resolve resources.
     * @param context Context to use to resolve resources.
     *
     * @return the resource wrapped around a XMLSignatureInput
     *
     * @throws ResourceResolverException
     */
    public abstract XMLSignatureInput engineResolveURI(ResourceResolverContext context)
        throws ResourceResolverException;

    /**
     * This method helps the {@link ResourceResolver} to decide whether a
     * {@link ResourceResolverSpi} is able to perform the requested action.
     *
     * @param context Context in which to do resolution.
     * @return true if the engine can resolve the uri
     */
    public abstract boolean engineCanResolveURI(ResourceResolverContext context);

}
